How can I transform Images from aces to bt.2020?

[frankC11]

Hey everyone, I'm new here and I don't know how to transform Images in another gamut. Is the command "colorconvert" the correct one? Can somebody help me please?

[lgritz]

The way we would usually do it is

oiiotool in.exr -colorconvert aces bt2020 -o out.exr

Now, there are a number of assumptions:

• You have an OpenColorIO config with those names corresponding to the right color spaces.
• Your $OCIO env variable points to the config (or you also add the --colorconfig /path/to/config to the oiiotool command)
• The OpenImageIO package was build with OpenColorIO present, so that support was built in. (You can confirm that with oiiotool --help -- at the bottom there should be information about OCIO support and which config it found.)

[lgritz]

The list of color spaces you see are no more and no less than whatever is in your OpenColorIO config.

[frankC11]

And what does the command --ociodisplay? Is it possible to combine this commands?

[lgritz]

Yes, you can chain together as many oiiotool commands as you want.

Docs on --ociodisplay:
https://openimageio.readthedocs.io/en/v2.4.7.1/oiiotool.html#cmdoption-ociodisplay

oiiotool --help will tell you all the displays and views that are available in your color configuration. (Or, for those readers building from the current master / in-progress 2.5, the command for this has changed to oiiotool --colorconfiginfo.)

[frankC11]

Thank you very much. What is the different between --ociodisplay and --colorconvert and do the known displays correspond to the ODTs?

[lgritz]

--colorconvert converts between two color spaces (given by name), and corresponds underneath to an OpenColorIO ColorConfig->getProcessor() call and applying it.

--ociodisplay corresponds underneath to an OpenColorIO DisplayViewTransform, and needs the names of the display, view, and optionally any looks to apply and the input color space.

I think if you need more detail about the differences, when these are appropriate, and exactly what they do in a color pipeline, it is probably better to ask on the OpenColorIO forums. They have a great Slack workspace with a "helpdesk" channel and are very responsive, with both the OCIO developers and the color scientists at several major studios quick to jump in and answer questions.